14 DAY TRIAL // Missiles were first launched 8 centuries ago by the Chinese, during their battles with the Mongols. The first Chinese missiles were propelled by gunpowder. When arrows and spears were stuck to it, the missile made a dreadful weapon. The Mongols were so impressed, that they made their own missiles employed against the Arabs. Arabs too assumed them and, from the Arabs, they passed into Europe.
In 1429, the French troops led by Joanne of Arc defended the city of Orleans against the English troops using missiles. But these ancient missiles went extinct, as they proved less precise than riffles.
Since 1500, rockets have been used for fireworks, for the first time in Italy, than in the whole Europe. Around 1700, missiles again played an important role in wars. In 1792, British troops fighting in India were bombarded by small rockets with a metal hull. They were so effective that William Congreve, director of the Woolwich Laboratory of London, decided to build them for the British. In 1804, he transformed the simple rocket into a mass destruction weapon, with much stronger explosion and fire power. Missiles' precision was improved in 1844, when William Hale introduced the stabilized torsion. The curbed propellers in the mouth of the evacuation hose made the rocket spin during its flight. This conferred stability, like the spin of a gyroscope. Shape or density irregularities were no more a problem. The spinning technique for stabilization had been achieved in 1400 for bullets, and in ancient times for arrows and spears.
To make a larger distance, a rocket had to be built bigger, in order to transport a larger amount of gunpowder or other fuel. But this meant a heavier rocket and propulsion on a longer distance was not possible. The solution was applied in 1855: when the back part was destroyed through burning, the explosive load separated the two parts and ignited the front part. This way, the first multi-level rocket made a longer distance than a simple rocket having the same weight, because only a part of the missile was sent towards the target. These rockets were first used to ignite shore rescue cables for periled ships.
During the First World War (1914-1918), British troops used ballistic missiles to bring down German aircrafts. The first missile with liquid fuel was made in 1926 in US, but in 1936, USSR achieved a record of this technology: a liquid fuel missile flew up to 5.6 km (3.5 mi). In 1944-1945, Germans built ballistic missiles, called V2, that allowed them to bombard the UK. The German technology for building V2 was assumed, after the Second World War, by the winning parties, US and USSR.
The Cold War boosted the development of the strategic missiles, carrying nuclear intercontinental bombs. US slowed down its program, waiting for the perfecting of a hydrogen compact bomb, requiring a relatively small carrying rocket. But USSR perfected larger rockets, capable of carrying larger atomic bombs.
Such large rockets enabled them to launch the first artificial satellite of the Earth, Sputnik 1, in October 1957. The space epoch had started. Using German scientists, US reacted by sending its own satellite 4 months later and developing the Apollo program. The program used a three level giant rocket, Saturn V, which transported the first man on the Moon in 1969.
The third Newtonian law says that each action has an equal or opposite reaction. If you jump from a small boat to the shore, your action will push the boat away from the shore. Rockets function on the same principle. They are propelled by the emission of a matter flow, usually gas. The gases turn on a reaction power that moves the rocket. Rockets contain all they need for propulsion, unlike jet engines, which must receive air to burn the fuel. That's why rockets can be hermetically closed, allowing journeys in vacuum spaces.
In most rockets, a solid or liquid fuel is burned into a limited space and the resulting gases can get out through one to several hose mouths. The oxygen required for the burning can be achieved from a chemical (like potassium nitrate in the case of the gunpowder). In modern rockets with liquid fuel, oxygen is stored as liquid, being used for burning kerosene (a hydrocarbon) or hydrazine (a chemical containing nitrogen and hydrogen).
Solid fuel rockets are preferred because of their simplicity and security. They can be used like auxiliary appliances for acting parts from a multi-level rocket. But liquid fuel rockets deliver the power required for a complete space mission and their push can be easily controlled. At the same fuel amount, liquid fuel rockets deliver higher acceleration and propulsion than solid fuel rockets.
Yet, solid fuel rockets are used for investigating meteorological phenomena, carrying devices for measuring wind speed, atmosphere pressure, electromagnetism, radiation and for "seeding" the clouds.
Some missiles, like M88, have a speed doubling that of the sound.
In fact, liquid fuel rockets are rapid enough to go further than to the Moon or inside the Solar System. The spacecraft American Voyager 2 used Jupiter's gravitational force to speed up, coming off with a speed of 36,000 km (22,500 mi) per hour. But even this speed is too low to travel to other stars. The closest star to the Solar System is Proxima Centauri, located at about 40 million km (25 million mi) away. A spacecraft like Voyager would need 126,000 years to reach it. That's why faster rockets are being sought.
Nuclear powered rockets could not be launched from Earth because of the resulting dangerous radiation, but they could be launched from space. They would be fueled by a series of nuclear explosions. The heat from the nuclear reactor would boil a liquid which could be expelled as gas through the hose mouths.
Plasma hydrogen is considered as well. This is a flow of charged particles. A magnetic field would be used to force plasma from the rocket to produce the push. Another idea is to use an electric field to force mercury and cesium ions out of the rocket. The system works, but the propulsion is extremely low, one kilogram (2.2 pounds) for 4 million watts. But, through gradual acceleration along several months, the rocket would reach high speeds.
The photon rocket would receive power from the light rays emitted by its tail. But even a high concentration of light rays won't compete against the ion propulsion.